diff --git a/src/Polyfills/ExpectException.php b/src/Polyfills/ExpectException.php
index 6ec0e7b..07240fb 100644
--- a/src/Polyfills/ExpectException.php
+++ b/src/Polyfills/ExpectException.php
@@ -45,6 +45,8 @@ trait ExpectException {
 	 * Clear any stored exception information between each test.
 	 *
 	 * @after
+	 *
+	 * @return void
 	 */
 	public function clearExceptionInfo() {
 		$this->exceptionMessage = '';
diff --git a/src/TestListeners/TestListenerDefaultImplementationPHPUnit6.php b/src/TestListeners/TestListenerDefaultImplementationPHPUnit6.php
index 01cec17..93e1d97 100644
--- a/src/TestListeners/TestListenerDefaultImplementationPHPUnit6.php
+++ b/src/TestListeners/TestListenerDefaultImplementationPHPUnit6.php
@@ -27,6 +27,8 @@ trait TestListenerDefaultImplementation {
 	 * @param Test      $test Test object.
 	 * @param Exception $e    Instance of the error encountered.
 	 * @param float     $time Execution time of this test.
+	 *
+	 * @return void
 	 */
 	public function addError( Test $test, Exception $e, $time ) {
 		$this->add_error( $test, $e, $time );
@@ -40,6 +42,8 @@ public function addError( Test $test, Exception $e, $time ) {
 	 * @param Test    $test Test object.
 	 * @param Warning $e    Instance of the warning encountered.
 	 * @param float   $time Execution time of this test.
+	 *
+	 * @return void
 	 */
 	public function addWarning( Test $test, Warning $e, $time ) {
 		$this->add_warning( $test, $e, $time );
@@ -51,6 +55,8 @@ public function addWarning( Test $test, Warning $e, $time ) {
 	 * @param Test                 $test Test object.
 	 * @param AssertionFailedError $e    Instance of the assertion failure exception encountered.
 	 * @param float                $time Execution time of this test.
+	 *
+	 * @return void
 	 */
 	public function addFailure( Test $test, AssertionFailedError $e, $time ) {
 		$this->add_failure( $test, $e, $time );
@@ -62,6 +68,8 @@ public function addFailure( Test $test, AssertionFailedError $e, $time ) {
 	 * @param Test      $test Test object.
 	 * @param Exception $e    Instance of the incomplete test exception.
 	 * @param float     $time Execution time of this test.
+	 *
+	 * @return void
 	 */
 	public function addIncompleteTest( Test $test, Exception $e, $time ) {
 		$this->add_incomplete_test( $test, $e, $time );
@@ -73,6 +81,8 @@ public function addIncompleteTest( Test $test, Exception $e, $time ) {
 	 * @param Test      $test Test object.
 	 * @param Exception $e    Instance of the risky test exception.
 	 * @param float     $time Execution time of this test.
+	 *
+	 * @return void
 	 */
 	public function addRiskyTest( Test $test, Exception $e, $time ) {
 		$this->add_risky_test( $test, $e, $time );
@@ -84,6 +94,8 @@ public function addRiskyTest( Test $test, Exception $e, $time ) {
 	 * @param Test      $test Test object.
 	 * @param Exception $e    Instance of the skipped test exception.
 	 * @param float     $time Execution time of this test.
+	 *
+	 * @return void
 	 */
 	public function addSkippedTest( Test $test, Exception $e, $time ) {
 		$this->add_skipped_test( $test, $e, $time );
@@ -93,6 +105,8 @@ public function addSkippedTest( Test $test, Exception $e, $time ) {
 	 * A test suite started.
 	 *
 	 * @param TestSuite $suite Test suite object.
+	 *
+	 * @return void
 	 */
 	public function startTestSuite( TestSuite $suite ) {
 		$this->start_test_suite( $suite );
@@ -102,6 +116,8 @@ public function startTestSuite( TestSuite $suite ) {
 	 * A test suite ended.
 	 *
 	 * @param TestSuite $suite Test suite object.
+	 *
+	 * @return void
 	 */
 	public function endTestSuite( TestSuite $suite ) {
 		$this->end_test_suite( $suite );
@@ -111,6 +127,8 @@ public function endTestSuite( TestSuite $suite ) {
 	 * A test started.
 	 *
 	 * @param Test $test Test object.
+	 *
+	 * @return void
 	 */
 	public function startTest( Test $test ) {
 		$this->start_test( $test );
@@ -121,6 +139,8 @@ public function startTest( Test $test ) {
 	 *
 	 * @param Test  $test Test object.
 	 * @param float $time Execution time of this test.
+	 *
+	 * @return void
 	 */
 	public function endTest( Test $test, $time ) {
 		$this->end_test( $test, $time );
diff --git a/src/TestListeners/TestListenerDefaultImplementationPHPUnitGte7.php b/src/TestListeners/TestListenerDefaultImplementationPHPUnitGte7.php
index 71733a5..ed6d61c 100644
--- a/src/TestListeners/TestListenerDefaultImplementationPHPUnitGte7.php
+++ b/src/TestListeners/TestListenerDefaultImplementationPHPUnitGte7.php
@@ -27,6 +27,8 @@ trait TestListenerDefaultImplementation {
 	 * @param Test      $test Test object.
 	 * @param Throwable $t    Instance of the error encountered.
 	 * @param float     $time Execution time of this test.
+	 *
+	 * @return void
 	 */
 	public function addError( Test $test, Throwable $t, float $time ): void {
 		$this->add_error( $test, $t, $time );
@@ -40,6 +42,8 @@ public function addError( Test $test, Throwable $t, float $time ): void {
 	 * @param Test    $test Test object.
 	 * @param Warning $e    Instance of the warning encountered.
 	 * @param float   $time Execution time of this test.
+	 *
+	 * @return void
 	 */
 	public function addWarning( Test $test, Warning $e, float $time ): void {
 		$this->add_warning( $test, $e, $time );
@@ -51,6 +55,8 @@ public function addWarning( Test $test, Warning $e, float $time ): void {
 	 * @param Test                 $test Test object.
 	 * @param AssertionFailedError $e    Instance of the assertion failure exception encountered.
 	 * @param float                $time Execution time of this test.
+	 *
+	 * @return void
 	 */
 	public function addFailure( Test $test, AssertionFailedError $e, float $time ): void {
 		$this->add_failure( $test, $e, $time );
@@ -62,6 +68,8 @@ public function addFailure( Test $test, AssertionFailedError $e, float $time ):
 	 * @param Test      $test Test object.
 	 * @param Throwable $t    Instance of the incomplete test exception.
 	 * @param float     $time Execution time of this test.
+	 *
+	 * @return void
 	 */
 	public function addIncompleteTest( Test $test, Throwable $t, float $time ): void {
 		$this->add_incomplete_test( $test, $t, $time );
@@ -73,6 +81,8 @@ public function addIncompleteTest( Test $test, Throwable $t, float $time ): void
 	 * @param Test      $test Test object.
 	 * @param Throwable $t    Instance of the risky test exception.
 	 * @param float     $time Execution time of this test.
+	 *
+	 * @return void
 	 */
 	public function addRiskyTest( Test $test, Throwable $t, float $time ): void {
 		$this->add_risky_test( $test, $t, $time );
@@ -84,6 +94,8 @@ public function addRiskyTest( Test $test, Throwable $t, float $time ): void {
 	 * @param Test      $test Test object.
 	 * @param Throwable $t    Instance of the skipped test exception.
 	 * @param float     $time Execution time of this test.
+	 *
+	 * @return void
 	 */
 	public function addSkippedTest( Test $test, Throwable $t, float $time ): void {
 		$this->add_skipped_test( $test, $t, $time );
@@ -93,6 +105,8 @@ public function addSkippedTest( Test $test, Throwable $t, float $time ): void {
 	 * A test suite started.
 	 *
 	 * @param TestSuite $suite Test suite object.
+	 *
+	 * @return void
 	 */
 	public function startTestSuite( TestSuite $suite ): void {
 		$this->start_test_suite( $suite );
@@ -102,6 +116,8 @@ public function startTestSuite( TestSuite $suite ): void {
 	 * A test suite ended.
 	 *
 	 * @param TestSuite $suite Test suite object.
+	 *
+	 * @return void
 	 */
 	public function endTestSuite( TestSuite $suite ): void {
 		$this->end_test_suite( $suite );
@@ -111,6 +127,8 @@ public function endTestSuite( TestSuite $suite ): void {
 	 * A test started.
 	 *
 	 * @param Test $test Test object.
+	 *
+	 * @return void
 	 */
 	public function startTest( Test $test ): void {
 		$this->start_test( $test );
@@ -121,6 +139,8 @@ public function startTest( Test $test ): void {
 	 *
 	 * @param Test  $test Test object.
 	 * @param float $time Execution time of this test.
+	 *
+	 * @return void
 	 */
 	public function endTest( Test $test, float $time ): void {
 		$this->end_test( $test, $time );
diff --git a/src/TestListeners/TestListenerDefaultImplementationPHPUnitLte5.php b/src/TestListeners/TestListenerDefaultImplementationPHPUnitLte5.php
index 810ae4b..631e2b1 100644
--- a/src/TestListeners/TestListenerDefaultImplementationPHPUnitLte5.php
+++ b/src/TestListeners/TestListenerDefaultImplementationPHPUnitLte5.php
@@ -33,6 +33,8 @@ trait TestListenerDefaultImplementation {
 	 * @param PHPUnit_Framework_Test $test Test object.
 	 * @param Exception              $e    Instance of the error encountered.
 	 * @param float                  $time Execution time of this test.
+	 *
+	 * @return void
 	 */
 	public function addError( PHPUnit_Framework_Test $test, Exception $e, $time ) {
 		$this->add_error( $test, $e, $time );
@@ -46,6 +48,8 @@ public function addError( PHPUnit_Framework_Test $test, Exception $e, $time ) {
 	 * @param PHPUnit_Framework_Test    $test Test object.
 	 * @param PHPUnit_Framework_Warning $e    Instance of the warning encountered.
 	 * @param float                     $time Execution time of this test.
+	 *
+	 * @return void
 	 */
 	public function addWarning( PHPUnit_Framework_Test $test, PHPUnit_Framework_Warning $e, $time ) {
 		$this->add_warning( $test, $e, $time );
@@ -58,6 +62,8 @@ public function addWarning( PHPUnit_Framework_Test $test, PHPUnit_Framework_Warn
 	 * @param PHPUnit_Framework_AssertionFailedError $e    Instance of the assertion failure
 	 *                                                     exception encountered.
 	 * @param float                                  $time Execution time of this test.
+	 *
+	 * @return void
 	 */
 	public function addFailure( PHPUnit_Framework_Test $test, PHPUnit_Framework_AssertionFailedError $e, $time ) {
 		$this->add_failure( $test, $e, $time );
@@ -69,6 +75,8 @@ public function addFailure( PHPUnit_Framework_Test $test, PHPUnit_Framework_Asse
 	 * @param PHPUnit_Framework_Test $test Test object.
 	 * @param Exception              $e    Instance of the incomplete test exception.
 	 * @param float                  $time Execution time of this test.
+	 *
+	 * @return void
 	 */
 	public function addIncompleteTest( PHPUnit_Framework_Test $test, Exception $e, $time ) {
 		$this->add_incomplete_test( $test, $e, $time );
@@ -80,6 +88,8 @@ public function addIncompleteTest( PHPUnit_Framework_Test $test, Exception $e, $
 	 * @param PHPUnit_Framework_Test $test Test object.
 	 * @param Exception              $e    Instance of the risky test exception.
 	 * @param float                  $time Execution time of this test.
+	 *
+	 * @return void
 	 */
 	public function addRiskyTest( PHPUnit_Framework_Test $test, Exception $e, $time ) {
 		$this->add_risky_test( $test, $e, $time );
@@ -91,6 +101,8 @@ public function addRiskyTest( PHPUnit_Framework_Test $test, Exception $e, $time
 	 * @param PHPUnit_Framework_Test $test Test object.
 	 * @param Exception              $e    Instance of the skipped test exception.
 	 * @param float                  $time Execution time of this test.
+	 *
+	 * @return void
 	 */
 	public function addSkippedTest( PHPUnit_Framework_Test $test, Exception $e, $time ) {
 		$this->add_skipped_test( $test, $e, $time );
@@ -100,6 +112,8 @@ public function addSkippedTest( PHPUnit_Framework_Test $test, Exception $e, $tim
 	 * A test suite started.
 	 *
 	 * @param PHPUnit_Framework_TestSuite $suite Test suite object.
+	 *
+	 * @return void
 	 */
 	public function startTestSuite( PHPUnit_Framework_TestSuite $suite ) {
 		$this->start_test_suite( $suite );
@@ -109,6 +123,8 @@ public function startTestSuite( PHPUnit_Framework_TestSuite $suite ) {
 	 * A test suite ended.
 	 *
 	 * @param PHPUnit_Framework_TestSuite $suite Test suite object.
+	 *
+	 * @return void
 	 */
 	public function endTestSuite( PHPUnit_Framework_TestSuite $suite ) {
 		$this->end_test_suite( $suite );
@@ -118,6 +134,8 @@ public function endTestSuite( PHPUnit_Framework_TestSuite $suite ) {
 	 * A test started.
 	 *
 	 * @param PHPUnit_Framework_Test $test Test object.
+	 *
+	 * @return void
 	 */
 	public function startTest( PHPUnit_Framework_Test $test ) {
 		$this->start_test( $test );
@@ -128,6 +146,8 @@ public function startTest( PHPUnit_Framework_Test $test ) {
 	 *
 	 * @param PHPUnit_Framework_Test $test Test object.
 	 * @param float                  $time Execution time of this test.
+	 *
+	 * @return void
 	 */
 	public function endTest( PHPUnit_Framework_Test $test, $time ) {
 		$this->end_test( $test, $time );
diff --git a/src/TestListeners/TestListenerSnakeCaseMethods.php b/src/TestListeners/TestListenerSnakeCaseMethods.php
index e21ef4a..8985de6 100644
--- a/src/TestListeners/TestListenerSnakeCaseMethods.php
+++ b/src/TestListeners/TestListenerSnakeCaseMethods.php
@@ -20,6 +20,8 @@ trait TestListenerSnakeCaseMethods {
 	 * @param Test                $test Test object.
 	 * @param Exception|Throwable $e    Instance of the error encountered.
 	 * @param float               $time Execution time of this test.
+	 *
+	 * @return void
 	 */
 	public function add_error( $test, $e, $time ) {}
 
@@ -31,6 +33,8 @@ public function add_error( $test, $e, $time ) {}
 	 * @param Test    $test Test object.
 	 * @param Warning $e    Instance of the warning encountered.
 	 * @param float   $time Execution time of this test.
+	 *
+	 * @return void
 	 */
 	public function add_warning( $test, $e, $time ) {}
 
@@ -40,6 +44,8 @@ public function add_warning( $test, $e, $time ) {}
 	 * @param Test                 $test Test object.
 	 * @param AssertionFailedError $e    Instance of the assertion failure exception encountered.
 	 * @param float                $time Execution time of this test.
+	 *
+	 * @return void
 	 */
 	public function add_failure( $test, $e, $time ) {}
 
@@ -49,6 +55,8 @@ public function add_failure( $test, $e, $time ) {}
 	 * @param Test                $test Test object.
 	 * @param Exception|Throwable $e    Instance of the incomplete test exception.
 	 * @param float               $time Execution time of this test.
+	 *
+	 * @return void
 	 */
 	public function add_incomplete_test( $test, $e, $time ) {}
 
@@ -58,6 +66,8 @@ public function add_incomplete_test( $test, $e, $time ) {}
 	 * @param Test                $test Test object.
 	 * @param Exception|Throwable $e    Instance of the risky test exception.
 	 * @param float               $time Execution time of this test.
+	 *
+	 * @return void
 	 */
 	public function add_risky_test( $test, $e, $time ) {}
 
@@ -67,6 +77,8 @@ public function add_risky_test( $test, $e, $time ) {}
 	 * @param Test                $test Test object.
 	 * @param Exception|Throwable $e    Instance of the skipped test exception.
 	 * @param float               $time Execution time of this test.
+	 *
+	 * @return void
 	 */
 	public function add_skipped_test( $test, $e, $time ) {}
 
@@ -74,6 +86,8 @@ public function add_skipped_test( $test, $e, $time ) {}
 	 * A test suite started.
 	 *
 	 * @param TestSuite $suite Test suite object.
+	 *
+	 * @return void
 	 */
 	public function start_test_suite( $suite ) {}
 
@@ -81,6 +95,8 @@ public function start_test_suite( $suite ) {}
 	 * A test suite ended.
 	 *
 	 * @param TestSuite $suite Test suite object.
+	 *
+	 * @return void
 	 */
 	public function end_test_suite( $suite ) {}
 
@@ -88,6 +104,8 @@ public function end_test_suite( $suite ) {}
 	 * A test started.
 	 *
 	 * @param Test $test Test object.
+	 *
+	 * @return void
 	 */
 	public function start_test( $test ) {}
 
@@ -96,6 +114,8 @@ public function start_test( $test ) {}
 	 *
 	 * @param Test  $test Test object.
 	 * @param float $time Execution time of this test.
+	 *
+	 * @return void
 	 */
 	public function end_test( $test, $time ) {}
 }
diff --git a/tests/Polyfills/AssertClosedResourceShmopTest.php b/tests/Polyfills/AssertClosedResourceShmopTest.php
index fc28bed..d4bb37f 100644
--- a/tests/Polyfills/AssertClosedResourceShmopTest.php
+++ b/tests/Polyfills/AssertClosedResourceShmopTest.php
@@ -35,6 +35,8 @@ final class AssertClosedResourceShmopTest extends AssertClosedResourceTestCase {
 	 * while we need two.}
 	 *
 	 * @before
+	 *
+	 * @return void
 	 */
 	protected function skipOnIncompatiblePHP() {
 		if ( \PHP_VERSION_ID < 70000 || \PHP_VERSION_ID >= 80000 ) {
diff --git a/tests/Polyfills/AssertFileDirectoryTest.php b/tests/Polyfills/AssertFileDirectoryTest.php
index 8b52737..59d4ed6 100644
--- a/tests/Polyfills/AssertFileDirectoryTest.php
+++ b/tests/Polyfills/AssertFileDirectoryTest.php
@@ -40,6 +40,8 @@ public function testAssertIsReadable() {
 	 *
 	 * This exception was thrown until PHP 7.0.0. Since PHP 7.0.0, a PHP native TypeError will
 	 * be thrown based on the type declaration.
+	 *
+	 * @return void
 	 */
 	public function testAssertIsReadableException() {
 		try {
@@ -100,6 +102,8 @@ public function testAssertNotIsReadable() {
 	 * be thrown based on the type declaration.
 	 *
 	 * @requires PHPUnit < 10.0.0
+	 *
+	 * @return void
 	 */
 	public function testAssertNotIsReadableException() {
 		try {
@@ -158,6 +162,8 @@ public function testAssertIsWritable() {
 	 *
 	 * This exception was thrown until PHP 7.0.0. Since PHP 7.0.0, a PHP native TypeError will
 	 * be thrown based on the type declaration.
+	 *
+	 * @return void
 	 */
 	public function testAssertIsWritableException() {
 		try {
@@ -218,6 +224,8 @@ public function testAssertNotIsWritable() {
 	 * be thrown based on the type declaration.
 	 *
 	 * @requires PHPUnit < 10.0.0
+	 *
+	 * @return void
 	 */
 	public function testAssertNotIsWritableException() {
 		try {
@@ -276,6 +284,8 @@ public function testAssertDirectoryExists() {
 	 *
 	 * This exception was thrown until PHP 7.0.0. Since PHP 7.0.0, a PHP native TypeError will
 	 * be thrown based on the type declaration.
+	 *
+	 * @return void
 	 */
 	public function testAssertDirectoryExistsException() {
 		try {
@@ -336,6 +346,8 @@ public function testAssertDirectoryNotExists() {
 	 * be thrown based on the type declaration.
 	 *
 	 * @requires PHPUnit < 10.0.0
+	 *
+	 * @return void
 	 */
 	public function testAssertDirectoryNotExistsException() {
 		try {
diff --git a/tests/Polyfills/ExpectExceptionTest.php b/tests/Polyfills/ExpectExceptionTest.php
index ac2bf38..79b3dec 100644
--- a/tests/Polyfills/ExpectExceptionTest.php
+++ b/tests/Polyfills/ExpectExceptionTest.php
@@ -59,6 +59,8 @@ public function testExpectExceptionCode() {
 	 * this method as it needs union types.
 	 *
 	 * @requires PHPUnit < 7
+	 *
+	 * @return void
 	 */
 	public function testExpectExceptionCodeException() {
 		$test   = new InvalidExceptionCodeTestCase( 'test' );
diff --git a/tests/TestListeners/Fixtures/TestListenerImplementation.php b/tests/TestListeners/Fixtures/TestListenerImplementation.php
index 1980126..6e34266 100644
--- a/tests/TestListeners/Fixtures/TestListenerImplementation.php
+++ b/tests/TestListeners/Fixtures/TestListenerImplementation.php
@@ -75,6 +75,8 @@ class TestListenerImplementation implements TestListener {
 	 * @param Test                $test Test object.
 	 * @param Exception|Throwable $e    Instance of the error encountered.
 	 * @param float               $time Execution time of this test.
+	 *
+	 * @return void
 	 */
 	public function add_error( $test, $e, $time ) {
 		++$this->errorCount;
@@ -86,6 +88,8 @@ public function add_error( $test, $e, $time ) {
 	 * @param Test    $test Test object.
 	 * @param Warning $e    Instance of the warning encountered.
 	 * @param float   $time Execution time of this test.
+	 *
+	 * @return void
 	 */
 	public function add_warning( $test, $e, $time ) {
 		++$this->warningCount;
@@ -97,6 +101,8 @@ public function add_warning( $test, $e, $time ) {
 	 * @param Test                 $test Test object.
 	 * @param AssertionFailedError $e    Instance of the assertion failure exception encountered.
 	 * @param float                $time Execution time of this test.
+	 *
+	 * @return void
 	 */
 	public function add_failure( $test, $e, $time ) {
 		++$this->failureCount;
@@ -108,6 +114,8 @@ public function add_failure( $test, $e, $time ) {
 	 * @param Test                $test Test object.
 	 * @param Exception|Throwable $e    Instance of the incomplete test exception.
 	 * @param float               $time Execution time of this test.
+	 *
+	 * @return void
 	 */
 	public function add_incomplete_test( $test, $e, $time ) {
 		++$this->incompleteCount;
@@ -119,6 +127,8 @@ public function add_incomplete_test( $test, $e, $time ) {
 	 * @param Test                $test Test object.
 	 * @param Exception|Throwable $e    Instance of the risky test exception.
 	 * @param float               $time Execution time of this test.
+	 *
+	 * @return void
 	 */
 	public function add_risky_test( $test, $e, $time ) {
 		++$this->riskyCount;
@@ -130,6 +140,8 @@ public function add_risky_test( $test, $e, $time ) {
 	 * @param Test                $test Test object.
 	 * @param Exception|Throwable $e    Instance of the skipped test exception.
 	 * @param float               $time Execution time of this test.
+	 *
+	 * @return void
 	 */
 	public function add_skipped_test( $test, $e, $time ) {
 		++$this->skippedCount;
@@ -139,6 +151,8 @@ public function add_skipped_test( $test, $e, $time ) {
 	 * A test started.
 	 *
 	 * @param Test $test Test object.
+	 *
+	 * @return void
 	 */
 	public function start_test( $test ) {
 		++$this->startTestCount;
@@ -149,6 +163,8 @@ public function start_test( $test ) {
 	 *
 	 * @param Test  $test Test object.
 	 * @param float $time Execution time of this test.
+	 *
+	 * @return void
 	 */
 	public function end_test( $test, $time ) {
 		++$this->endTestCount;